"I have seen it and the boy certainly tugs him in the box," said the United manager.

"If you look the referee is two yards away from it and decided to give it.

"All I know is he got a penalty kick from a decision, I don't know anything about reputations or anything.

"The referee was there. He made quite a lot of decisions tonight and that one he gave a penalty kick."

Sociedad coach Jagoba Arrasate was less certain.

"I couldn't really see it from the dug-out," he said. "The player kind of folds. I would need to see all the replays from the TV."

Keane was not the only ex-United player to condemn Young.

Ray Wilkins shared the Irishman's thoughts, saying: "This is pathetic. This is as bad for me as all these over-the-top tackles we're getting at the moment because that is a conning of the referee.

"I just wish Ashley would cut this out because he's a good player but he's getting a bad name."

Former defender Paul McGrath - who like Young played for United and Aston Villa - feels the 28 year-old is detracting from what he can do on the field.

"I was disappointed with Ashley Young," he told talkSPORT. "That was never a penalty.

"I genuinely believe he is a very good player but he's got into this habit of tripping himself up if anyone bumps into him in the penalty area.

"It takes away from the fact he's a brilliant footballer. He's going to be left with the perception he's the one who always dives in the penalty area.

"It's not good for Manchester United and it's not good for kids to see him doing that. I hate to see any player doing that sort of thing."

That Van Persie missed probably took some of the sting out of the situation, with the eventual 0-0 scoreline meaning United will advance to the Champions League knockout stage if they win one of their remaining two fixtures.

Wayne Rooney backed his fellow striker to bounce back from his spot-kick failure, saying: "Of course [everyone misses from time to time].

"Most forwards in the world miss penalties. That won't affect him, I'm sure."

United will be without Marouane Fellaini when they visit Bayer Leverkusen in three weeks' time after the Belgian was sent off in stoppage time for two yellow card offences.

"As I said earlier regarding the penalty kick the referee made decisions all night," said Moyes.

"He is the one who must have seen fit both to award a penalty and send a player off.

"I thought he made some strange decisions all night and that was another one of them."

The incidents took the heat off Javier Hernandez, whose failure to turn home Shinji Kagawa's second-half cross from six yards was inexplicable for a player of his undoubted class, who has scored three times in his last two games.

"The miss from Javier was an opportunity," said Moyes.

"To be fair to him the ball bobbled up. It just comes off the ground a little bit before it gets to him.

"But he gets in those positions week in week out and that is where he gets his goals from."